(1) Field of the Invention:
The present invention relates to an imaging light-sensitive material which can be widely used for graphic design, for formation of printing masters and for preparation of printing plates. More particularly, the present invention relates to an imaging material having a three-layer structure including a transparent substrate, a polyamide layer containing an alcohol-soluble polyamide and a light-sensitive photoresist layer.
(2)Description of the Prior Art:
An imaging material having a three-layer structure as described above is well-known as disclosed in Japanese Patent Application Laid-Open Specification No. 116303/77. On such imaging material, an image is formed by exposure to light, and then developing and etching are conducted in sequence. As regards means for forming an image according to these procedures, we previously proposed in Japanese Patent Applications Nos. 35210/79 and 27522/79 an improved method in which the developing and etching are accomplished simultaneously with one treating solution.
These conventional imaging methods, however, involve problems to be solved on actual operations, for example, insufficient latitude of the etching operation, insufficient sharpness of the formed image (insufficient latitude of the developing) and insufficient mechanical strength of the formed image.
We made researches with a view to solving these problems from various viewpoints, for example, on the treating solution for forming images in the above-mentioned previously proposed method. As the result, we proposed, for example, a light-sensitive photoresist composition as disclosed in Japanese Patent Applications Nos. 31579/79, 38092/79, 38093/79 and 36370/79.
Throughout our researches, it was found that in the imaging material of the above-mentioned type, the solution of the foregoing problems is greatly influenced by the thicknesses of the light-sensitive photoresist layer and the polyamide layer. More specifically, it was found that an imaging light-sensitive material having a three layer structure including a transparent substrate, [I] a polyamide layer containing an alcohol-soluble polyamide as the major component and having a thickness of from 2 to 11 microns and [II] a light-sensitive photoresist layer having a thickness of from 0.5 to 5 microns is well-balanced in the developing property, etching property, mechanical strength of the formed image and actinic opacity and is very excellent as the imaging material. We have now completed the present invention based on this finding.